题目

After disappearing for over 19 years, measles (麻疹) is making a comeback in America. Since January 2019, the disease has infected more than 700 people, mostly small children, and the number seems to be increasing daily.Measles is an infectious disease that typically begins with a high fever, cough, runny nose, and red, watery eyes. Many people also lose their appetites and feel sleepy. About three to four days after the symptoms start, the person breaks out into a rash (皮疹) that begins on the face at the hairline and then spreads to the neck and the rest of the body.In healthy people, t下图为外界物体在视网膜上成像的示意图，据图回答问题。（1）远处物体反射来的光线，经过［ ］_____的折射，在［ ］_____上形成物像。（2）青少年如果用眼不当，会造成近视，近视眼的预防应该做到“_____”和“_____”。（3）外界物体反射来的光线会在眼内成像，产生神经冲动，然后通过［ ］_____传递到_____，产生视觉。（4）近视眼可以配带_____加以矫正。